Flexible high-performance cable system has passed the toughest tests

Excellent transmission properties and a long service life under extreme motion – these are the challenges that machine tool and automation equipment manufacturers pose for systems with flexible cables. Even high-performance networks with 10 GB/second Ethernet must fulfil these requirements in the industrial Ethernet environment. igus and Telegaertner have worked together to create a cabling solution which has passed the toughest practical tests with sufficient reserves. The combination of chainflex cables and MFP8 RJ45 plug connectors offers outstanding transmission characteristics even after millions of cycles.

Individual components of a cabling path were tested by the manufacturer for conformity to standards in a laboratory. This ensures the user that the fully assembled solution functions reliably over time; in addition, we have demonstrated that this can pass strict, practical tests. This applies in particular to solutions with flexible cables which are subjected to high mechanical stresses.

igus® and Telegaertner therefore decided to join forces and test various assembled cabling solutions in their laboratories. The focus was on product solutions with highly flexible cables for Ethernet and PROFINET applications. These are used in nearly all areas of automation equipment, in which large volumes of data must be transmitted quickly and reliably in more and more applications.

chainflex®: Developed for flexible applications

chainflex® cables from igus were developed for use in moving energy chain systems, and have been proven in many different application areas. Among others, Cat. 6A cables CFBUS.050 with a TPE outer jacket were tested, in which the conduit elements were braided with an especially short pitch length. The precise, very tightly braided overall screen and four protection pairs offer reliable and durable protection against outside electrical influences. chainflex bus cables with PVC and PUR sheaths were also tested.

Connectors with special wire terminations

The RJ45 modular connectors in the MFP8 series from Telegaertner are characterized by their innovative and especially reliable wire terminations. The individual wires in a cable are pulled through during manufacturing. The special piercing technique provides especially stable connections with outstanding transmission values. The connector can be made in the field, and can be installed even within tight space limitations on-site without special tools. The wires are reliably contained in specially-sized chambers without free play, so that a stable, positive connection is ensured with optimal signal transfer.

Telegaertner uses a reliable, innovative technology called „Insulation Piercing Contact” (IPC) for cable diameters which commercially-available RJ45 crimp connectors cannot accept. It has proven itself not only in industrial applications, but also in power networks for telecommunication and in high-value IT patch cables for durable, reliable contacts. In IPC technology, the fine wires of a braided conductor are not simply clamped between two displacement connectors (IDCs), as with conventional technology; rather, they are pulled through at three spatially offset locations. This pioneering technology offers outstanding, long-term stable contacts and additional safety under tensile stresses which cannot always be avoided in practical applications.

Complete testing far beyond the norm

igus® and Telegaertner have worked together in testing with a clear distribution of tasks. The igus® laboratory specializes in stress testing and mechanical movement in real applications. Up to 700 tests are running in parallel in a test area of 1,750 m². The Telegaertner laboratory is one of the leading measurement and testing laboratories for high-frequency measurements of connectors and assembled cables. The core is Telegaertner’s own developed real-time re-embedded measurement structure, which doesn’t test the relevant parameters one after another, but rather concomitantly in real time, and thus works much more precisely than is required by the IEC 60512 standards series requirements. Telegaertner measurement adapters are therefore used in leading independent measurement laboratories.

Both companies have forged pioneering work in testing highly-flexible industrial cables. The current version of the EN 60352 standard describes only measurement processes for cables with massive, one-wire cables and flexible, seven-wire braids. Measurement processes for automation engineering require cables with 19-wire, highly flexible braided wires; this standard does not include them. The pioneering combination of such braided Category 6 and 6A braided cables and innovative connectors using IPC technology can be seen as a breakthrough technology far beyond the current standards.

When Ethernet cables are deployed in moving applications in energy chains in automation equipment, they must meet high requirements with regard to their service life and load-bearing capacity.

The MFP8 RJ45 connector from Telegaertner can be assembled in the field; it offers reliable contacts with fusion of the contact elements.

Endurance testing: The manufactured cables are subjected to more than one million double strokes. This is followed by thorough electrical testing.

The polished cut image after completion of the testing shows: The combination of CFBUS cable and MFP8 connector exceeds CAT 6 or 6A standards even with highly-flexible application.

  Testing related to practice

The assembled cables for energy chains have been subjected to linear movements with over one million cycles. The transmission parameters of cabling systems which have been subjected to these stresses were then measured in accordance with strict Cat. 6A specifications up to 500 MHz as per ISO/IEC 11801. All samples tested demonstrated outstanding transmission quality. No defects were found either inside the cables or in the link to the connector. Final destructive testing of workpieces, in which the compounds were filled with casting resin and polished for microscopic examination, showed perfect contact images: The contacts were completely intact, as at the beginning, the fixation was as solid and reliable as at the beginning, and no play was found in the connection chamber of the plug connectors. Building on the test results with cablear movements, a torsion test was run at +/- 180°/m in order to simulate typical movements for robot applications. Cables with a different structure were used here; these were also able to withstand the most demanding special needs for robotics.

Result: Outstanding suitability for Ethernet and Profinet

The test results showed in general that the combination of MFP8 connectors and chainflex bus cables is particularly well-suited to provide the highest reliability in highly flexible cabling systems in automation devices, and to ensure Ethernet connections even at high data rates up to 10 GB/second. The cable solutions tested showed no recognizable wear and no impact on signal transmission even after several million cycles. This was also confirmed in other test series. The assembled cables thus fully conform to Ethernet standards in the important Cat. 6 and 6A categories. Even within the lower requirements of Cat. 5, which play an important role in Profinet applications, chainflex cables with MFP8 connectors from Telegaertner provide outstanding reliability.